#include <stdio.h>
#include <stdlib.h>

struct Node {
  int x;
  struct Node *s;
};

int main() {
  struct Node* n1 = (struct Node *) malloc(sizeof(struct Node));
  struct Node* n2 = (struct Node *) malloc(sizeof(struct Node));
  struct Node* n3 = (struct Node *) malloc(sizeof(struct Node));
  n1->x = 100; n1->s=n2;
  n2->x = 200; n2->s=n3;
  n3->x = 300; n3->s=NULL;
}